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morayfirthaudio

Dimming a 750w Bulb

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morayfirthaudio

Aye Aye :) What a cracking forum :) I stumbled upon this by accident, but I wish I found it years ago :) 

OK I digress, This is out of my remit as Im all Pro sound with a little Electrical knowledge :) But I found in an old Cupboard 2 750w Bulbs LES, These are big, so I thought about putting them in the Living room (Not On the Ceiling :) ) but as a feature because the elements are long and large, but... I want to Dim them right down so they glow and not burn my retinas out :) So it looks like Ill need a Variac to do this, but can you think of any other way?

Thanks for any help

Kindest

Glen

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Tony S

You don’t mention the voltage so I’ll assume 240V. One my best photographs is of a 300W GES lamp (please note it’s a lamp, not a bulb). To take the shot took a lot of messing about with the voltage so I used a Variac.

 

For a decorative lamp about 40W should be a reasonable light but it will be very red/orange.

 

Lamps resistance = 77Ω.

 

For 2 x 40W, 56V is required but this wouldn’t a standard off the shelf 100VA transformer. I’ll leave to you to look for something within your budget.

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Tony S

Just had wavy brain moment.

 

Connect the two lamps in series you could use a standard 240/110V transformer.

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Geoff1946

Why not a good old fashioned triac based dimmer?

 

Cold resistance is quite misleading as it changes dramatically as the lamp heats up.

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morayfirthaudio

Thanks Guys :)  Sorry I should have said its 240v, I have 2 of these Bulbs so I can use them both if need be.

Ive had a hunt on ebay for a Variac and were looking at about £150, (Thump!) so I thought if they could be wired in Series and then pop a Dimmer in place? 

The Dimmer Racks we use have a pre heat on them with a variable voltage but we cant get it up high enough to make the bulbs glow, They will glow but it needs to be pitch black so we need a tiny bit more voltage. 

So you think that a Variac is the only answer?

Thanks for all your help so far :) 

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Ardet R

If you wire the lamps in series and just use a standard 400W dimmer switch you should be OK.

Wiring them in series will dim them quite a lot and then the dimmer could be used to get the intensity you want.

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Richard-the-ninth

Have you tried a 1000w dimmer? click here

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morayfirthaudio

Hi There, Just to say thanks for all your advice, the winner is....Ardet R :)  I grabbed a cheap 400w Dimmer from toolstation, not confident that it would work, but I took it home, Popped both Bulbs in Series and tune it on and it works better than perfect ;)  I can pop up some pictures if you are really bored :) 

Thanks once again :) 

Cheers

Glen

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roys

Thanks for getting back to us Glen, yip get the pics might have to get Admin to give you pic permission as it is not automatic until you have 10 posts.

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morayfirthaudio

No Probs, Ill grab it this weekend, Can we upload Videos? as That might be better? :) 

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Blue Duck

paste a YouTube link and it should be embedded into the forum ;)

 

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Ardet R

I am glad it works to your satisfaction, it is always nice to be able to keep it simple.

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morayfirthaudio

Im not too sure if this will work but its a like to Facebook - 

 

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roys

That works well, dog doesn't move much though😀

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